I have previously bought and sold the M3 Lee. I now have enough free xp to go back and research the M4 Sherman and enough credits to buy it. However when I go to Tech Tree to research the vehicle the "research" tab is greyed out. Do I have to buy the Lee again to do this research? I was told in chat that I don't need to but don't know why "research" is greyed out if this is correct. I have more than the 14055 xp required to do the research for the M4 Sherman as free credits. Anyone know anything about this?
Now in order to research the M4 you have to first research the 75mm Gun in the "M3 Lee-Research Modules" before you can research the M4 Sherman that's why it's greyed out even if you get a million free xp you most unlock (research) the modules that leads to the tank you wish to unlock (research).. do this and get back to me asap.